a) You never trust your life to any single device and there are always backup plans if something fails. And at recreational depths you're not going to do severe damage if your watch fails and you lose no decompression limit information.
b) The watch is such a joy to use underwater. It's 100x brighter and clearer than other devices so you see information at a glance. It actually made the whole diving experience better it was that good.
c) I've had Apple Watches since the original one and reliability has always been excellent. Easily on par with other dive computers. And of course the ease and quality of the user experience is significantly better.
I've had numerous activity tracking apps crash on me randomly, I think because they have been running out of memory on my Apple Watch 3. Strava was one of them. I stopped using it for this purpose after I lost a few tracks.
Either that or the watch is throttling to prevent browning out, and the app crashes as a result of loops / event handling not happening fast enough and stuff 'piling up.'
Except for more advanced (deeper) dives, a dive computer is fairly unnecessary. 700 lbs of air pressure left, go back up, slowly.
I did most of my diving right off the coast of san diego, where there are amazing kelp forests. I preferred less deep dives (35-50 feet) anyway... you start going deep, you have much less air/time down below.
I would assume this to be a very tiny market for users.
But both the backup regulator and dice computer is on your companion. You don’t dive with two yourself.
You get air tanks that have 2 mounts for first stage and the octo goes into the separate first stage, giving you two independent setups.
I've only seen crazy swiss people do that though.
While it is used primarily in cave diving because it is more streamlined and less likely to collide with cave ceilings and features, I find it also quite comfortable for recreational dives with a pair of AL40s.
It’s also a fun conversation starter with other divers who are curious about my gear!
Backup dive computers are much less common and most people use their buddy as their backup computer. It is much safer to surface without a functioning dive computer than it is to surface without a functioning regulator.
You're entirely welcome to have backups. I dive with 2 lights, and if the Apple Watch didn't require a subscription I'd gladly buy it to also dive with 2 computers. My divemaster had a second bottle with its own independent octopus for cave diving.
Anything you can afford to double (both financially and in terms of practicality/weight/encumbrance), by all means, go ahead and do it. Triple it if makes sense.
Every dive I've done has been on a boat with quite a few people all doing the same sites during the day. If your computer failed you can still estimate NDL from others on the boat and just err on the side of caution. Or even just rely on paper charts like people did for decades.
If you're doing cave diving then obviously a whole different story.
For that reason the Apple Watch Ultra seems just fine - it doesn't seem to have any less features than my dedicated Suunto D5 (outside missing integration with air tank) and it seems to be a good competitor to Garmin's Descent MK2 series of diving computers (which are pretty amazing but cost 1200$+ with tank pods).
Nonetheless, from the press release: “Always follow diving protocols and dive with a companion and have a secondary device.”
I think it’s very much not recommended to have going computerless as a backup. And the idea that you are safe to do so because your “within no-deco limits” is potentially dangerous, as your relying on the computer to tell you if you are still within that limit.
Many people go quite close to the limit. Personally I stay far away from them, but safety recommendations are the same for everyone.
The backup plan for recreational open water diving would typically be to end the dive if your computer fails, not to continue computerless. At the point that your computer failed, you should have been within no-deco limits, which you can confirm with your partner's computer to a reasonable margin of safety, so you can ascend safely.
I'm curious to see what they have for using it with diver communication and collaboration. If one diver sees something of interest, they can easily notify other divers. I'm not sure if or how well Bluetooth works underwater?
The haptic vibration would be useful to notify about reaching maximum bottom time, and for decompression rest stops while ascending.
But I think I would still keep my traditional dive computer next to pressure gauge in my diving setup.
I wonder if they will have a wireless pressure sensor on the tank so you can also track air pressure and consumption? That would be neat.
Water tends to block most radio signals pretty quickly. If you are trying to wirelessly transmit data underwater you get much, much better range with sound than you do with light.
It doesn’t, which is why heart rate monitors intended for swimming activities have on-board storage.
The fact that water absorbs 2.4ghz light is what enables microwave ovens to heat water in the first place. So while it's an inconvenient property during dives, it's very convenient in the kitchen.
If you're a casual diver (i.e. two dives a day on vacation, maybe a night dive here and there) you don't need a computer at all
You call the dive and surface slowly. Maybe you don’t do a second dive if you can’t be sure of your limits. It’s an inconvenience.